{"id":640,"date":"2022-01-07T00:50:23","date_gmt":"2022-01-06T21:50:23","guid":{"rendered":"https:\/\/labsensors.org\/?page_id=640"},"modified":"2022-01-08T17:21:34","modified_gmt":"2022-01-08T14:21:34","slug":"proekt-20-07-00139","status":"publish","type":"page","link":"https:\/\/labsensors.org\/en\/reports\/proekt-20-07-00139\/","title":{"rendered":"Project &#8220;Backward acoustic waves in strong anisotropic materials and structures based on such materials&#8221;"},"content":{"rendered":"<p><strong>Project 20-07-00139 &#8220;Backward acoustic waves in strong anisotropic materials and structures based<\/strong><br \/>\n<strong>on such materials&#8221;<\/strong><br \/>\nOne of the types of acoustic waves propagating in the plates are backward acoustic waves with<br \/>\ndifferent polarizations. The phase and group velocities of these waves are directed in different<br \/>\ndirections. The aim of this project is a theoretical and experimental study of the features of the<br \/>\nexcitation and propagation of backward acoustic waves in highly anisotropic materials and<br \/>\nstructures based on them and containing, inter alia, piezoelectric and piezosemiconductor layers<br \/>\nunder various boundary conditions. In 2021, within the framework of the project, the features of<br \/>\nthe propagation of backward acoustic waves in structures containing a highly anisotropic<br \/>\nmaterial TeO2 and piezoelectric semiconductor layers made of gallium arsenide were<br \/>\ninvestigated. Earlier, crystallographic orientations of TeO2 were found, at which the existence of<br \/>\nbackward acoustic Lamb waves of various types is possible. The backward acoustic<br \/>\nantisymmetric wave of the first order (A1), which exists in TeO2 at Euler angles \u03c6 = \u03b8 = \u03c8 = 0,<br \/>\nis studied in detail. At this stage, the influence of a layer made of a piezoelectric semiconductor<br \/>\nmaterial (gallium arsenide) on the characteristics of this wave was investigated. It was found<br \/>\nthat, as in the case of a layer with a strong piezoelectric, with an increase in the thickness of the<br \/>\npiezoelectric semiconductor layer, the velocity of the backward wave increases, and the point<br \/>\nwith zero group velocity shifts to the region of lower frequencies. It should be noted that, in the<br \/>\ncase of a piezoelectric semiconductor, this displacement is greater than in the case of a strong<br \/>\npiezoelectric, despite the weak piezoelectric effect. This is due to the conductivity of the layer<br \/>\nmaterial. In this case, the type of wave did not change. The influence of an infinitely thin layer<br \/>\nwith arbitrary conductivity on the characteristics of the backward wave A1 in the structure<br \/>\n&#8220;TeO2 plate &#8211; GaAs plate&#8221; was also investigated. It is found that the bulk conductivity of the<br \/>\nGaAs plate almost completely screens the TeO2 piezoelectric effect, which leads to almost<br \/>\ncomplete absence of the influence of the layer with arbitrary conductivity, which is in contact<br \/>\nwith the piezoelectric plate from the back side, on the velocity of backward acoustic waves.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Project 20-07-00139 &#8220;Backward acoustic waves in strong anisotropic materials and structures based on such materials&#8221; One of the types of acoustic waves propagating in the plates are backward acoustic waves with different polarizations. The phase and group velocities of these waves are directed in different directions. The aim of this project is a theoretical and [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":538,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-640","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages\/640","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/comments?post=640"}],"version-history":[{"count":2,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages\/640\/revisions"}],"predecessor-version":[{"id":649,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages\/640\/revisions\/649"}],"up":[{"embeddable":true,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages\/538"}],"wp:attachment":[{"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/media?parent=640"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}